They're usually sociopaths (or psychopaths, whatever you want to call them). They can fake empathy and other emotions that bond people with other living, conscious things... but on the inside, their brains are incapable of actually feeling those emotions. They care only about themselves.

Your Dog will Haunt the Fugitive of your complex Emotion. Find Comfort in the sweeter of the Memories you have with the Animal. People do thing's like this because the Media Teach them and program them, to behave like this. Extreme Complexities in our Social Climate- here in America.

Very sorry for your loss, some people are just animal haters. There was a dog in my street that was poisoned a couple of years ago by a neighbor, he got caught as he didn't know they had security cameras installed. Apparently the reason he did it was because the dog barked continuously whenever the owners were out, but he had other options to deal with it and it was just awful for the poor dog. Humans scare me sometimes.

I AM SOOOO SORRY....The person needs to be found and prosecuted...I hope you reported this to the police..and to the newspapers...SERIOUSLY....Don't take this...
This person could well be a psychopath..many serial killers are this way....It is not just mean...it is murder...Don't let this person get away with this ...others will lose their animals as well...

I wish I knew, dude.
I had a cat that died "mysteriously"... I'm pretty damn sure my neighbour did something to her. They said they found her dead but circumstances say otherwise. I've been very cautious about my pets ever since, even tho those people have moved.
Sorry to hear about your dog. Hope he didn't suffer.

It's horrible that there are such mean people out in the world who would harm an animal,
That is the reason my cat is an indoor one.And the only time he can be closest to being out side is when my door or window is opened and the both of them are screened

whether we like it or not there seems to be some fraction of the human population that despite the complexity of the human brain there are so many people on the planet these days in the right commotions that many people just aren't given the chance to be fully human and to use that brainpower to their fullest. an aggressiveness towards other species used to be useful but now in the 21st century its the first sign of a not-so-awesome example of humanity. partially thankful to many of today's modern religions people wants to believe themselves to be something superior to the rest of the animal kingdom when in truth our intelligence is nothing but our particular evolutionary advantage that takes alot more education than we get in high school to explain why we know this.

sentience is a far more complex thing than even its obtaining species realizes, capable of such great things but yet such horrible evils. throughout history almost all issues get better over time but are never really resolved, at least not yet. it may seem like an entire different discussion but technology provides solutions to all problems and is just a matter of funding the projects to produce them, i hate to make it sound like it all comes down to money but if it makes you feel any better it also takes a special genius which i've already seen being done